FLOOD00898

• County: Statewide
• Title: Floods in Colorado
• Date: 6/1/1948
• Prepared For: State of Colorado
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

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CONTENTS
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Malar flonda-Continued.
ArkaD88S River-Continued.
lluerfano FUver___________________________________________
ApmhapalUver___________________________________________
I'nrgatoheIUver__________________________________________
Wolf Creek and Qr&n&da ereek_____________________________
TWo Butte Creek_n_.______________________________________
WildIIorae Creek_________________________________________
Minor tributaries of Arkansas River_________________________
EUo (}rsnde___________________________________________________
South Fork Rio Grande____________________________________
AI8lUoaa Creek____________________________________________
Conejos River.............. ____.... __ __.... __.. _____ .....___ __ _.... __.. ____
Colorado River u_n_ _ __ _ ___ n___ n n __ _ __ _ _ _ _ _ _ n n n__ u __ ___
<lunnmonItiver___________________________________________
lJncoDlpahgJe ltiver___________________________________
lDolores FUver_____________________________________________
West Creok___________________________________________
San Miguel River_____________________________________
SanJuanFtiver__________________~________________________
Animas River __ ___.. __.... __ __ __ ___ __ _ _ ___ _____ __ ___ _ ____
La Plata River________________________________________
Summary of maximum flood disoharges..________________n__________
Changes in channel capacity and development of flood-protection measures
Index____________________________________________________________

ILLUSTRATIONS

PLAT., 1. City of Denver during tbellood of May 19-20, 1864__________
2. Damage to Denver & Rio Grande Railroad caused by flood of
June 1921: A. Bridge weat of Pueblo; B, Railroad yarda in
Pueblo_________________________________________,______
3. Damage to tracks of Denver &: Rio Grande Railroad caused by
flood of October 1911 on San Juan River near PagosaJunctioD_
FlGllBB 1. Map of Colorado showing principal river systems and cities
mentioned in the text________________________.._________
2, Typical atago hydrograpba of cloudburst floods__,______,___,
3. Chart shOWing maximum flood discharge~ in second-feet per
equare mile, for various places given in the summAry table__

The first records of floods in Colorado antedated the settlement of the State
by about 30 yearB. These were records of floods on the ArkanS9.8 and Republican
Rivers in 1826. Other floods noted by traders, hunters and emigrants, some
of whom were on their way to the Far West, occurred in 1844 on the Arkansas
River. and by inference on the South Platte River. Other early floods were those
on the Purgatoire, the Lower Arkansas, and the San Juan Rivers about 1~59.
The most serious flood since settlement bega.n was that on the ArkansaB River
during June 1921, which caused the loss of about 100 Uves and an estimated
property loBS of $19,000,000. Many floods of lesser magnitude have occurred.
and some of these bave caused lOBS of life and very considerable property damage.
Topography is the chief factor in determining the location of storms and ~e-
suIting floods. These occur most frequently on the eastern slope of the Front
Range. In the mountains farther west precipitation is insufficient to cause floods
except during periods of melting snow, in June. In the southwestern part of the
State, where precipitation during periods of melting snow is insufficient to cause
floods, the severest floods yet experienaed resulted from heavy rains in September
1909 and October 191\.
In the eastern foothills -region, usual1y below an altitude of about 7,500 feet
and extending for a distance of about 50 miles east of the mountains, is a zone
subject to rainfalls of great intensity known as cloudbursts. These cloudbursts
are of short duration and are confined to very amall areas. At times the intensity
is so great as to make breathing difficult for those exposed to a storm. The areas
of intense rainfall are so small that Weather Bureau precipitation stations have
not been located in them. Local residents, being cloudburst conscious, frequently
measure the rainfall in receptacles in their yards, and such records constitute the
only source of information regarding the intensity. .
A flood resulting from a cloudburst rises so quickly that it is usually described
as a uwall of water." It has a peak dura.tion of o~ly a few minutes, followed by
a rapid subsidence. Nearly 90 cloudburst floods in Color&do are described in
varying detail in this report. The earliest recorded cloudburst-called at that
time a waterspoutr-occurred in Golden Gate Gulch, July 14, 1872. The uwall of
water" was described as a tlperpendicular breast of 10 or 12 feet." A cloudburst
flood on Kiowa Creek in May 1878 caused the loss of a standard-gage locomotive.
and although search was made by means of long metallic rods, the locomotive was
never recovered, as bedrock was about 50 feet below the creek bed.
All available information relative to floods in Colorado, beginning with the
flood of 1826 on the Arkansas River, is presented in thia report, although for many
of the earlier floods estimates of discharge are lacking.
Floods throughout a large part of the State have occurred in 1844, June 1864,
June 1884, May 1894, and June 1921. The highest floods of record were on the
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FLOODS IN COLORADO

By ROBERT FOLLANSBEE AND LEON R. SAWYER

ABSTRACT

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